Oven door hinge

ABSTRACT

A structure especially useful as a hinge to support an oven door comprising a spring which is self contained within a casing and a counter balancing system operatively connected between the door and the spring together with latch mechanism operative during assembly of the hinge to the oven to lock the hinge in a partially open position so that the same cannot close and injure the assembler and damage the oven.

United States Patent [1 1 Kleinhenn OVEN DOOR HINGE [75] Inventor:Walter H. Kleinhenn, Flourtown, Pa.

[73] Assignee: United Filtration Corporation, Chicago, Ill.

[22] Filed: Mar. 2, 1972 [21] Appl. No.: 231,126

[52] US. Cl 126/191, 126/194, 16/146 [51] Int. Cl. F23m 7/00 [58] Fieldof Search 126/191, 194;

[56] References Cited UNITED STATES PATENTS 3,503,380 3/1970 Vasaturo126/191 3,067,736 12/1962 Barefoot 126/194 Primary ExaminerCarroll B.Dority, Jr. Attorney-Frederick J. Olsson [57] ABSTRACT 6 Claims, 13Drawing Figures PATENIEUJ I 3. 749 .080

sum 1 [IF a PATENTEUJUL3 1 ma SHEEI 2 0F 4 FIGS FIG.2

PATENTED 1 I975 3. 749.080

' sum u [If a OVEN DOOR HINGE This invention relates to hingesespecially suitable for supporting drop type oven doors for freestanding or built in ovens.

The conventional cook oven has a hollow body with an access door hingedto the bottom. The door is rotatable in a vertical direction, as betweena closed position wherein the door extends vertically and an openposition where the door extends generally horizontally, In the closedposition the door seals off the oven and in its horizontal position thedoor provides for access to the interior of the oven. A door of the kinddescribed is commonly referred to as a drop type door. For broilingpurposes such ovens provide for the door to be held slightly spaced fromthe closed position and this is commonly called the broil position.

In the broil position the door may be taken off the hinges, cleaned andthen replaced.

The hinges of the invention are especially adapted for supporting thedoor of ovens of the type described above. While in the material belowreference is made to a single hinge, this is done for ease ofdescription and it will be understood that two identical hinges are usedone on each side of the door.

The hinges of the invention are a substantial improvement inself-contained, spring loaded oven hinges of the kind shown in U.S. Pat.No. 3,503,380 and in copending application Ser. No. 74,815 filed Sept.23, 1970 and now abandoned.

The assembly of such hinges to the oven requires the hinge to be placedin a partially open or broil position. The assembler must be careful notto strike the hinge because the same may dislodge from the detentholding the hinge in broil. Upon such dislodgement the spring willquickly and forcefully move the hinge to the closed position. Thisexposes the operator's fingers to cutting or even fracture. When theoven is equipped with a stainless steel or porcelain rim, the same canbe irreparably damaged. Thus the assembler must exercise caution andperform the assembly operation very slowly and this slows downproduction.

The dangers expressed above are also present when the housewife removesthe oven door, for example, the hinge could be dislodged by the doorstriking the hinge just as the door is lifted off or when the door isjust about to be replaced. In either case, damage to the oven isinevitable. Injury to the fingers is also a distinct possibility.

Thus the principal object of the invention is to provide a hinge andlatch mechanism which will automatically lock the hinge in partiallyopen position during assembly and when the door is removed for cleaningbut which will be automatically deactivated when the door is mounted onthe hinge.

The preferred forms of the invention will be described below inconnection with the following drawings wherein:

FIG. 1 is a side elevational view of a hinge embodying the invention,the hinge being in the door-open position;

FIG. 2 is a side elevational view of the hinge of FIG. 1 in thepartially open or broil position;

FIG. 3 is a side elevational view of the hinge of FIG. 1 in the doorclosed position;

FIG. 4 is an elevational view looking toward the left in FIG. 3;

FIG. 5 is a fragmentary plan view showing latch components of the hingeof FIG. 1;

FIG. 6 is a fragmentary elevational view of certain of latch componentsof the hinge of FIG. 1, the view being taken from the back side of FIG.1;

FIG. 7 is an elevational view of a hinge having a modified embodiment ofthe invention the hinge being in the partially open or broil position;

FIG. 8 is a fragmentary view of certain latch components of the hinge ofFIG. 7;

FIG. 9 is an elevational view of the hinge of FIG. 7 in the closedposition;

FIG. I0 is an elevational view of a hinge embodying a modified form ofthe invention, the hinge being in the partially open or broil position;

FIG. 11 is a view of the hinge of FIG. 10 in closed position;

FIG. 12 is a view taken along the lines 12-12 of FIG. 10 andillustrating latch components; and

FIG. I3 is a view similar to FIG. 12 but with the latch mechanism ininoperative position.

With respect to the description of FIGS. 1 thru 13 which follows,it-will be understood that the door has been removed from the hinge.

As shown in FIG. 1 the hinge structure includes the elongated housing orcasing 1 which is constructed to be fixed in a vertical position on theframe of the oven. The hinge has a carrier arm 2 which is pivotallyconnected to the casing as by the pivot mechanism 3. The arm mounts theoven door and provides for the same to be rotatable as between the open,broil and closed positions. The arm is interconnected with the casing byoperating mechanims providing for the various rotational positions.

In FIG. 1 the hinge is in the open position, with the carrier arm 2extending generally horizontally. In this position the door is locked onthe arm and cannot be removed.

In FIG. 2 the carrier arm is in partially open or broil position. In thebroil position, the door can be lifted off the arm and then replaced.

In FIG. 3 the carrier arm is in the closed position. It will be notedthat the arm is somewhat angularly oriented with respect to thevertically extending casing. Actually, when the door is on the arm thesame extends more vertically than as shown in FIG. 3. This is to permitthe spring-detenting arrangement (which will be explained later) to holdthe door in tight engagement with the oven.

The casing I is U-shaped in cross section and the back of the casing hasa pair of inwardly extending flanges 4. The front or bottom of thecasing is indicated at 5.

Preferably the oven door is equipped with a socket. The door is mountedon the carrier arm as by sliding the socket straight down over tha arm.The door is automatically locked in position except for removal purposesas mentioned above. In FIG. I the socket is generally indicated bydot-dash lines 6 and the door is indicated by the heavy dotted lines 7.The socket is U- shaped in cross section with the mouth of the U beingfixed to the inside plate I0 of the door. The socket is open ended atIll and closed at 12 so that the end 13 of the arm abuts against the endof the socket. The bottom M of the socket fits along the lower edge ofthe carrier arm and sides 15 and 16 (see FIG. 5) abut the off-set 20, 2and 22 of the carrier arm. The bottom 14 is provided with a smallopening (not shown) which receives the latch 23 which functions to lockthe door on the arm.

A pivot bracket 24 is mounted directly on the bottom of the casing 1 andhas the pivot means 3 which rotatably connects the carrier, bracket andthe casing with the carrier arm.

With respect to the structure of the door 7, it will be understood thatan opening is provided which is aligned with the socket 6 and whichaccomodates the pivot bracket 24 and carrier arm 2. For a typicaldoorsocket-oven arrangement of the kind described above reference may behad to U.S. Pat. No. 3,505,380.

A lever arm in indicated at 25. The lever arm is connected to thecarrier arm as by the pivot 26. The pivot 26 provides for the lever armand the carrier arm to be relatively rotatable.

Disposed within the casing l is slide bracket 30 which is movable up anddown the casing. The bracket is retained by the flanges 4. The bracketcarries an operating shaft 31 which extends thru the elongated slot 32formed on the lever arm. The shaft 31 operating in the slot 32 forms apivot means which provides for the lever and bracket to be relativelyrotatable. The slot 32 permits relative sliding motion as between thebracket 30 and the lever arm 25 for purposes as will be apparent as thedescription proceeds.

It will be apparent from the inspection of FIG. 1 that with rotarymotion of the carrier arm 2, the bracket 30 partakes of a sliding motionalong the casing or conversely with sliding motion of the bracket 30 thecarrier arm rotates. If the carrier arm moves counterclockwise as viewedin FIG. 1, the bracket slides down the casing and vice versa.

The open position of the hinge is defined by the engagement of thecarrier arm tail 33 with the bottom of the casing. The closed positionof the hinge is defined by the shoulder 34 on the carrier arm engagedwith the lanced section 35 on the pivot bracket.

The broil or partially open position is defined by a detentingarrangement and a locking mechanism which will be explained later.

A compression spring 36 is disposed within the casing 1. The top end ofthe spring is connected to the casing via the bracket 37. At the bottom,the spring is engaged with the bracket 30 and exerts a force thereon.The spring is retained in the casing as by the flanges 4. When the dooris in the open position the spring is fully compressed (FIG. 1) andexerts its greatest force.

When the door is in the closed position the spring is partially expanded(FIG. 4) and exerts the least force. The force of the spring 36 istransmitted thru the bracket 30, pivot 31, lever arm 25 and thence tothe carrier arm 2.

The spring develops a torque on the carrier arm around the pivot 3. Thistorque acts to rotate the arm to the closed positioon.

When the door is mounted on the carrier arm and moved as between theopen and broil positions, the weight of the door creates a torque on thecarrier arm acting around the pivot 3 in a direction opposite to thetorque created by the spring 36.

When the door is in the open position, the effective weight of the doorgenerates the largest torque with respect to the pivot 3 and thecompression spring 36 being fully compressed, also exerts the maximumtorque with respect to the pivot 3. As the door begins to move clockwisetoward the broil position the effective weight becomes less and thespring 36, by expanding, commensurately generates less torque. Theweight of the door is counter balanced by the force of the compressionspring 36. As understood in the trade, the term counter balancing meansa force which may be of a magnitude simply to overcome part of the doorweight so that the door is easier to swing upwardly or downwardly or mayrefer to a force of magnitude which is enough to effectively cancel outthe weight of the door whereby the door will remain stationary if placedin any position between open and broil.

The latch 23 is carried by a latch arm 38 connected to the carrier armas by pivot 39. The spring 40 mounted on the carrier arm normally biasesthe latch arm so that the latch 23 extends outwardly as indicated inFIG. 1. As previously indicated this locks the door on the carrier arm.The outward position of the latch is determined by the engagement of theboss 41 on the latch arm 38 engaging the bottom of the aperture 42 inthe carrier arm (FIG. 6).

When the carrier arm approaches the broil position the followers or camrollers 44 and 45 (see FIG. 4) mounted on the pivot shaft 31 becomeoperative respectively to effect the detenting or holding of the arm inthe broil position and the disabling of the latch 23 as explained below.

As the carrier arm approaches the broil position the surface 46 on thearm engages the cam roller 44 and with further rotation the detent 50accepts the roller 44. It will be noted that the pin 31 is spaced awayfrom the bottom of the slot 32. This allows the pressure of spring 36 tobe transmitted from the bracket 30, pin 31 directly to the roller 44 sothat the roller is held tightly in the detent 50. The foregoingstructure forms a holder mechanism which holds the carrier arm (and ovendoor) in the broil or partially open position.

Also with the approach of the carrier arm to the broil position thesurface 51 on the latch arm engages the cam roller 45 and this causesthe latch arm 41 to be rotated clockwise against the force of the spring40. The latch 23 moves out of the slot in the socket. Withoutinterference from the latch 23, the door can be lifted off the carrierarm.

When the carrier arm is moved from the broil position toward the closedposition the cam roller 44 runs along surface 52 on the carrier arm.This lifts the roller 44 and pivot shaft 31 upwardly, the latter motionbeing accomodated by the fact that the pivot shaft 31 is free to moveupwardly in the slot 32. The spring 36 therefore exerts pressure on thebracket 30, the shaft 31 and on the roller 44 which forces the carrierarm to the closed position. When a door is mounted on the carrier arm,the arm assumes a more vertical position than is indicated in FIG. 3,accordingly the surface 52 is contoured so that the force of the springis effective to maintain the door closed.

Also in the closed position. the surface 53 of the lever arm engages thecam roller 45 so that the lever arm remains substantially in the sameposition as it was in the broil position. If desired, the surface 53 onthe latch arm can be formed so that the latch 23 assumes its lockingposition when the carrier arm is in the closed position.

As mentioned heretofore one of the principal features of the inventionis a latch or holder mechanism to secure the arm in the broil position(or partially open position) during assembly of the hinge to the ovenand when the door is removed for cleaning. This is explained following.

When the hinge is free from the door and the carrier arm is in the broilposition it will normally stay in such position provided it is notjarred of otherwise knocked out of detent 50.

The hinge is mounted on the oven by securing the casing to the back sideof the oven frame. The oven frame has a slot which allows the pivotbracket and carrier arm to project outwardly in front of the oven forreceiving the door. The slot accommodates motion of the carrier arm.

In some ovens the frame is open and the portion to which the hinge isattached is readily accessible from the outside. Other ovens areconstructed so that the portion on which the hinge is attached isenclosed within a cover or housing.

With the first type of oven the hinge is put into broil position, thecasing is held in the fingers and the hinge moved so that the carrierarm and pivot bracket are inserted thru the frame slot and the bottom 5of the casing 1 is brought up to the back part of the frame. The casingis then secured in place.

With the second type of oven, the hinge is put into the broil position,the carrier arm held in the fingers, the hinge moved so that the casingis inserted thru the frame slot and then brought up on the back side ofthe frame and secured in place.

With either type of oven, the assembler must exercise caution to avoidjarring the hinge because this causes the arm to come out of the broildetent and to be moved very rapidly and firmly to the closed position bythe spring. If the operator's fingers are between the carrier arm andthe casing there is great danger of cutting and fracture of fingers.Moreover, if the hinge closure takes place while the hinge is beinginserted or is secured in place by the carrier arm, by moving to theclosed position will strike and damage any stainless steel or porcelainbezel or rim on the oven frame. As a consequence, the assembler mustmove slowly and carefully and this cuts down production.

It will be understood that the same danger of injury and damage arepresent when the door is removed for cleaning.

The invention provides a latch and latch control mechanism thereforwhich will automatically lock the arm in the broil position when thecarrier arm is free from the door, but which will be renderedinoperative when the door is on the carrier arm. With latch arrangement,the carrier arm cannot be jarred loose from the broil position and thusinjury to the assembly personnel and damage to ovens are eliminated andproduction of ovens increased and that the consumer's ovens and fingersare likewise protected.

With reference to FIGS. 1, 5 and 6 the latch is in the form of a barwhich extends thru slot 55 in the carrier arm and is adapted to be movedalong the slot from one. end to the other. The bar rotates with thecarrier arm.

As shown in FIG. 1, the bar 54 is positioned at the inner end of theslot 55 which is the operative position. The bar occupies a radialposition with respect to the pivot 3 which is the same as the radialposition of a locking land 56 formed in pivot bracket 24. Therefore,when the carrier arm is rotated clockwise the bar will engage the land56. With engagement of bar 54 and land 56 the force of spring 36 cannotmove the carrier arm to the closed position. The land 56 is located sothat the carrier arm is stopped at the broil position.

When the bar is at the outer end of slot 55 which is the inoperativeposition it occupies a radial position with respect to the pivot 3 whichis the same as the radial position of the recess 5'7 formed on the pivotbracket 24. Therefore when the carrier arm is rotated clockwise the barwill slip into the recess 57 and the bar will not offer interference tothe carrier arm moving to the closed position.

The bar MI is moved to the innermost radial position when the carrierarm is free from the door and is moved to outermost radial position whenthe door is placed on the carrier arm. The foregoing motion isaccomplished by a latch operating mechanism including a cam springarrangement.

The cam or actuating arm 60 is connected to the bar 54. A control spring61 is connected to the cam 60 and also is firmly crimped to the carrierarm as indicated at 62. When the carrier arm is free from the doorsocket, the spring 61 holds or biases the cam to the position shown inFIG. 1 so the bar 54 occupies its locking or operative position. Whenthe door is placed on the arm, the socket engages the cam 60 and pushesthe same so that the bar 54 moves to the outward or inoperative positionin slot 55.

The bar 541, cam or actuating arm 60 and control spring 61 are made froma unitary piece of spring steel wire so that a single wireform comprisesthe latch and latch control mechanism.

In FIGS. 7, 8 and 9 I have shown a modified form of the latch and latchoperating mechanism.

The bar 63 is rotatably mounted on the carrier arm as by pivot 64. Thecam 65 is connected tothe bar so as to be rotatable therewith. The latchspring 40 is modified as by that an end 66 extends downwardly to engagethe finger 70 on the cam. The end 66 forms a control spring. When thecarrier arm is free from the door socket the spring 66 biases the camand bar to rotate the same to the position shown in FIG. 7. As will beobserved the bar is in juxtaposition with respect to locking land 71 onthe pivot bracket 24. This is the operative locking position becausemotion of the carrier arm clockwise away from the broil position willcause the bar 63 to engage the land 71 and prevent rotation. The forceof the spring 36 cannot move the carrier arm out of the broil positionto the closed position.

When the door is put on the carrier arm, the door socket engages the cam65 and rotates the same clockwise to the position shown in FIG. 8. Thisplaces the bar 63 at an angle with respect to the locking land 71. Inthis position of the bar, rotation of the carrier arm will causeengagement between the end 63a of the bar and the locking land. Withfurther carrier arm rotation, the engagement will affect a clockwiserotation of the bar 63 to the position as shown in FIG. 9. The bar willoffer no resistance to rotation of the carrier arm to the closedposition.

FIGS. l0, l1, l2 and 13 illustrate another embodiment of the latchingarrangement.

A bar 73 is rotatably mounted on the shaft 74 supported by the post 75fixed to the pivot bracket 24. The bar is positioned adjacent a slot 76formed in the pivot bracket. .The carrier arm also has a slot 80. Whenthe carrier arm is in the broil position of FIG. 10 the two slots are inalignment.

Fixed to the bar 73 is a cam 81 which rotates in unison with the bar. Onthe shaft 74 is a control spring 82, one end 83 of which bears againstthe under side of the cam -81. The spring biases the cam and bar so thatthe bar tends to rotate into the slot 76 (into the paper as viewed inFIG.

Thus when the hinge is free from the socket and the carrier arm is inthe broil position, the spring 82 rotates the cam and bar to theposition as shown in FIG. 12. The bar 73 extends across the slots 76 and80 into the path of rotation of the carrier arm and prevents rotation ofthe carrier arm out of the broil position. This is the operative orlocking position of the bar 73 and the force of spring 36 cannot movethe carrier arm out of broil to closed position.

When the door is placed on the carrier arm the socket engages the cam 81and rotates the cam and bar to the position as shown in FIG. 13 out ofthe path of rotation of the carrier arm. The bar is now free from theslots and the carrier arm is rotatable. The position of the bar in FIG.13 is the inoperative position.

I claim:

1. A hinge structure for a cook oven having a hollow body with a doorproviding access to the body, the hinge permitting the door to rotaterelative to the body in a vertical direction as between open, partiallyopen and closed positions, the hinge comprising:

an elongated casing adapted to be mounted in a fixed position on thebody wherein the casing extends vertically and mounts the hinge on theoven;

a rotatable carrier arm constructed to fit into a socket on the ovendoor to thereby support the door for rotation therewith;

pivot means connecting the casing and the carrier arm and providing forthe arm to rotate relative to the casing in a vertical direction asbetween the open and closed positions;

operating mechanism including a compression spring connected between thecarrier arm and the casing, the spring exerting a force on the carrierarm to cause rotation of the arm toward the closed position when thecarrier arm is free from said socket;

latch means movable as between operative and inoperative positions; and

latch control mechanism for moving the latch to the inoperative positionwhen the carrier arm is in the door socket so that the latch does notinterfere with rotation of the carrier arm to closed position and alsofor moving the latch when the carrier arm is free from thedoor socket tothe operative position so that the latch holds the carrier against theforce of the spring in a partially open position, the latter positionbeing for use when the hinge is being assembled to the oven.

2. A construction in accordance with claim 1 wherein:

said pivot means includes a pivot bracket connected to the casing andextending outwardly therefrom, the bracket having a locking land formedthereon;

said latch means includes a bar extending thru a slot on the carrier armand movable as between opposite ends of the slot, one end of the slotbeing the operative position of the bar and the other end being theinoperative position;

said latch control mechanism includes a cam and a control spring, thecam being connected to the bar and adapted to engage the door socket andbe wherein:

said pivot means includes a pivot bracket connected to the casing andextending outwardly therefrom, the bracket having a locking land formedthereon;

said latch includes a bar mounted on said carrier arm for rotation asbetween the operative and inoperative positions;

said latch control mechanism includes a cam and a control spring, thecam being connected to the bar for rotation therewith and adapted toengage the door socket and be rotated in a direction to rotate the barto a position wherein rotation of the carrier arm out of the partiallyopen toward the closed position causes the bar to engage the lockingland and the engagement and further rotation of the carrier arm rotatingthe bar to the inoperative position and the control spring being mountedon the carrier arm and connected with the cam and biasing the cam torotate in a direction to rotate the bar to the operative positionwherein the bar engages the locking land at a predetermined position ofthe carrier arm to establish said partially open position.

4. A construction in accordance with claim 1 wherein:

said pivot means includes a pivot bracket connected to the casing andextending outwardly therefrom;

said latch means includes a bar mounted on said pivot bracket and a slotformed in said carrier arm for receiving said bar, the bar being mountedfor rotation between the operative and inoperative positions;

said latch control mechanism includes a cam and a control spring, thecam being connected to the bar for rotation therewith and adapted toengage the door socket and be rotated in a direction to rotate the barto the inoperative position wherein the bar cannot be received by saidcarrier arm slot and the control spring being mounted on the carrier armand connected with the cam and biasing the cam to rotate in a directionto rotate the bar to the operative position wherein the bar is receivedby the carrier arm slot at a predetermined position of the carrier armto establish said partially open poisition.

5. A construction in accordance with claim 1 wherein said operatingmechanism includes:

a lever arm;

pivot means connecting the lever arm to the carrier arm and providingfor the arms to be rotatable relative to one another;

a bracket slidably mounted on said casing;

pivot means connecting the lever arm and the bracket and providing forthe same to be rotatable relative to one another, one end of thecompression spring being connected to said bracket and said spring forcebeing transmitted to the carrier arm via the bracket and the lever arm.

6. A construction in accordance with claim 5 wherein said latch controlmechanism and said latch means are constructed from a single wireform.

* It i t i

1. A hinge structure for a cook oven having a hollow body with a doorproviding access to the body, the hinge permitting the door to rotaterelative to the body in a vertical direction as between open, partiallyopen and closed positions, the hinge comprising: an elongated casingadapted to be mounted in a fixed position on the body wherein the casingextends vertically and mounts the hinge on the oven; a rotatable carrierarm constructed to fit into a socket on the oven door to thereby supportthe door for rotation therewith; pivot means connecting the casing andthe carrier arm and providing for the arm to rotate relative to thecasing in a vertical direction as between the open and closed positions;operating mechanism including a compression spring connected between thecarrier arm and the casing, the spring exerting a force on the carrierarm to cause rotation of the arm toward the closed position when thecarrier arm is free from said socket; latch means movable as betweenoperative and inoperative positions; and latch control mechanism formoving the latch to the inoperative position when the carrier arm is inthe door socket so that the latch does not interfere with rotation ofthe carrier arm to closed position and also for moving the latch whenthe carrier arm is free from thedoor socket to the operative position sothat the latch holds the carrier against the force of the spring in apartially open position, the latter position being for use when thehinge is being assembled to the oven.
 2. A construction in accordancewith claim 1 wherein: said pivot means includes a pivot bracketconnected to the casing and extending outwardly therefrom, the brackethaving a locking land formed thereon; said latch means includes a barextending thru a slot on the carrier arm and movable as betWeen oppositeends of the slot, one end of the slot being the operative position ofthe bar and the other end being the inoperative position; said latchcontrol mechanism includes a cam and a control spring, the cam beingconnected to the bar and adapted to engage the door socket and be movedin a direction to move the bar to the inoperative position wherein thebar does not engage the locking land with rotation of the carrier arm,and the control spring being mounted on the carrier arm and connectedwith the cam and biasing the cam to move in a direction to move the barto the operative position wherein the bar engages the locking land at apredetermined position of the carrier cam to establish said partiallyopen position.
 3. A construction is accordance with claim 1 wherein:said pivot means includes a pivot bracket connected to the casing andextending outwardly therefrom, the bracket having a locking land formedthereon; said latch includes a bar mounted on said carrier arm forrotation as between the operative and inoperative positions; said latchcontrol mechanism includes a cam and a control spring, the cam beingconnected to the bar for rotation therewith and adapted to engage thedoor socket and be rotated in a direction to rotate the bar to aposition wherein rotation of the carrier arm out of the partially opentoward the closed position causes the bar to engage the locking land andthe engagement and further rotation of the carrier arm rotating the barto the inoperative position and the control spring being mounted on thecarrier arm and connected with the cam and biasing the cam to rotate ina direction to rotate the bar to the operative position wherein the barengages the locking land at a predetermined position of the carrier armto establish said partially open position.
 4. A construction inaccordance with claim 1 wherein: said pivot means includes a pivotbracket connected to the casing and extending outwardly therefrom; saidlatch means includes a bar mounted on said pivot bracket and a slotformed in said carrier arm for receiving said bar, the bar being mountedfor rotation between the operative and inoperative positions; said latchcontrol mechanism includes a cam and a control spring, the cam beingconnected to the bar for rotation therewith and adapted to engage thedoor socket and be rotated in a direction to rotate the bar to theinoperative position wherein the bar cannot be received by said carrierarm slot and the control spring being mounted on the carrier arm andconnected with the cam and biasing the cam to rotate in a direction torotate the bar to the operative position wherein the bar is received bythe carrier arm slot at a predetermined position of the carrier arm toestablish said partially open poisition.
 5. A construction in accordancewith claim 1 wherein said operating mechanism includes: a lever arm;pivot means connecting the lever arm to the carrier arm and providingfor the arms to be rotatable relative to one another; a bracket slidablymounted on said casing; pivot means connecting the lever arm and thebracket and providing for the same to be rotatable relative to oneanother, one end of the compression spring being connected to saidbracket and said spring force being transmitted to the carrier arm viathe bracket and the lever arm.
 6. A construction in accordance withclaim 5 wherein said latch control mechanism and said latch means areconstructed from a single wireform.